#include <iostream>
#include <string>
class Tree
{
	class node
	{
	public:
		node(char date)
			:_date(date)
			,_left(nullptr)
			,_right(nullptr)
		{}
		char _date;
		node* _left;
		node* _right;
	};
public:
	Tree()
		:_root(nullptr)
		,_equation(std::string())
	{}

	node* insert(std::string& s)
	{

	}

private:
	node* _root;
	std::string _equation;
};